Which of the following is the only taxonomic category that has a real existence?

Match the following genes of the $Lac$ operon with their respective products:
List-$I$ (Gene) | List-$II$ (Product)
$(i)$ $i$ gene | $(1)$ $\beta$-galactosidase
$(ii)$ $z$ gene | $(2)$ Permease
$(iii)$ $y$ gene | $(3)$ Repressor
$(iv)$ $a$ gene | $(4)$ Transacetylase
Select the correct option.

The product$(s)$ formed when $H_2O_2$ reacts with disodium hydrogen phosphate is

If $\alpha, \beta, \gamma$ are the roots of $x^3+4x+1=0$,then the equation whose roots are $\frac{\alpha^2}{\beta+\gamma}, \frac{\beta^2}{\gamma+\alpha}, \frac{\gamma^2}{\alpha+\beta}$ is

In a $CE$ transistor amplifier,the audio signal voltage across the collector resistance of $2\,k\Omega$ is $2\,V$. If the base resistance is $1\,k\Omega$ and the current amplification of the transistor is $100$,the input signal voltage is